Front-heavy dust cleaning vehicle

ABSTRACT

In one embodiment, a cleaning vehicle for cleaning a surface of an object includes first and second carriages (that define a frame). The vehicle also includes first and second wheels coupled to the first and second carriages to form a drive assembly and at least one motor is operatively coupled to at least one of the first and second wheels. A cleaning element extends between and is supported by the first and second carriages at a location forward of the first and second wheels. The vehicle also includes third and fourth wheels. The third wheel is adjustably mounted relative to the first wheel and the second traveler wheel is adjustably mounted relative to the second wheel. The third and fourth wheels are configured such that the object is received between the third and fourth wheels and the respective first and second carriages.

CROSS-REFERENCE TO RELATED APPLICATION

The present invention claims priority to U.S. patent application Ser.No. 62/209,047, filed Aug. 24, 2015, which is hereby incorporated byreference in its entirety.

TECHNICAL FIELD

The present invention generally relates cleaning vehicles and, moreparticularly, vehicles that have a cantilevered cleaning element.

BACKGROUND

Solar panels are a green alternative to generating electric power. Largescale power generation can include arrays of solar panels located inoutdoor environments for conversion of solar energy into electricalenergy. However, solar panels located in outdoor environments areexposed to sand, dust, dirt and other debris that can collect on thesurfaces of the solar panels and reduce the ability of the panels toabsorb light and convert it into electricity. This problem is magnifiedwhen panels are located in arid environments, such as deserts, whichreceive high levels of solar radiation and few overcast days becausethese environments tend to have high levels of dust and wind leading tohigh deposition rates on the surface of the panels.

The solar panels can be manually swept or otherwise cleaned; however,this process can be slow, labor intensive, costly, or have all of thesecharacteristics. The present invention is directed to these and otherproblems.

SUMMARY

In one embodiment, a cleaning vehicle for cleaning a surface of anobject includes first and second carriages (that define a frame) and anaxle extends between the first and second carriages. The vehicle alsoincludes first and second drive wheels coupled to the axle to form adrive assembly and at least one motor is operatively coupled to thedrive assembly. A cleaning element extends between and is supported bythe first and second carriages at a location forward of the first andsecond drive wheels. The vehicle also includes first and second travelerwheels. The first traveler wheel is adjustably mounted relative to thefirst drive wheel and the second traveler wheel is adjustably mountedrelative to the second drive wheel. The first and second traveler wheelsare configured such that the object is received between the first andsecond traveler wheels and the respective first and second carriages.

The vehicle is designed such that the cleaning element is disposed oneside of the axle (and the first and second drive wheels) and spacedtherefrom by a first distance, while the first and second travelerwheels are disposed on an opposite side of the axle and spaced therefromby a second distance.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

FIGS. 1A and 1B illustrate isometric views of the cleaning vehicledisposed on a solar panel according to a first embodiment of theinvention;

FIGS. 2A and 2B illustrate side views of the vehicle in a first andsecond condition;

FIG. 3 illustrates a rear view of the vehicle; and

FIG. 4 is a first side perspective view of a cleaning vehicle inaccordance with a second embodiment;

FIG. 5 is a second side perspective view of the cleaning device of FIG.4; and

FIG. 6 is a side view of a cleaning device in accordance with a thirdembodiment.

DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS OF THE PRESENT INVENTION

In accordance with one embodiment of the invention, referring to FIGS.1A and 1B, a surface cleaning vehicle 100 is disposed on a solar panelarray 10. The surface cleaning vehicle includes first and secondcarriages 102, 104 disposed on opposite ends of an axle 106. A first setof wheels comprised of first and second wheels 108, 110 are coupled tothe axle 106 and are disposed at opposite ends thereof, proximate torespective carriages 102, 104. A control housing 112 is supported by oneof the carriages 102, 104. The control housing 112 can include motors,control electronics, communication modules, a power source, etc., asdiscussed in more detail below. A cleaning element 114 extends betweenthe carriages 102, 104 and is supported thereby. A second set of wheelscomprised of third and fourth wheels 116, 118 are connected torespective carriages 102, 104 by adjustable couples 120, 122. Asdiscussed in more detail below, the first and second wheels 108, 110 andthe third and fourth wheels 116, 118 cooperate to couple the vehicle tothe solar panel array 10 so that the vehicle can traverse the surface ofthe array and maintain the cleaning element 114 in contact with thesurface of the array for cleaning.

As discussed in detail herein, in one embodiment, at least one of thefirst and second wheels 108, 110 can be a driven wheel, while the thirdand fourth wheels 116, 118 can be traveler wheels. However, as describedherein, in other embodiments, an opposite arrangement is possible inthat at least one of the third and fourth wheels 116, 118 is a drivenwheel and the first and second wheels 108, 110 can be traveler wheels.

The carriages 102, 104 provide the supporting structural framework ofthe vehicle 100. The axle 106 extends between the two carriages 102,104. Carriage 102 supports one end of the axle 106 and carriage 104supports the other end thereof. The axle 106 is coupled to the carriages102, 104 so that the axle 106 is free to rotate. First and second wheels108, 110 are coupled to the axle 106 at opposite ends thereof. The firstand second wheels 108, 110 are disposed proximate a respective carriage102, 104. The first and second wheels 108, 110 contact a top surface 12of the solar panel array 10. Accordingly, rotation of the axle 106causes a rotation of the first and second wheels 108, 110 such that thevehicle can traverse the solar panel array 10.

It will be appreciated that the axle 106 can be eliminated and instead adifferent type of structural support can be provided and disposedbetween the two carriages 102, 104 to provide a coupling of sufficientstrength between the two carriages 102, 104. For example, an aluminumextrusion can extend between the two carriages 102, 104. Alternatively,a sheet metal body/covering or any structural elements can be providedto couple the two carriages to one another. In addition, the brush core,described herein, can also provide structural rigidity between the twocarriages.

When axle 106 is eliminated, it will be appreciated that the first andsecond wheels 108, 110 are otherwise coupled to the two carriages 102,104 to permit free rotation of the first and second wheels 108, 110. Asdescribed herein, in one embodiment, only one of the first and secondwheel 108, 110 is driven and therefore, a single axle or drive shaftconnected between the one driven wheel 108, 110 and a drive motor(described herein) can be provided. Thus, a single axle connected toboth wheels 108, 110 is not required since an arrangement can beprovided in which only one of the wheels 108, 110 is actively driven,while the other wheel 108, 110 is passive (slave wheel).

The cleaning element 114 can be a brush that includes bristles. However,other types of cleaning devices such as pads or fabrics can be used. Thecleaning element 114 extends between the carriages 102, 104. Thecleaning element 114 is coupled to the carriages 102, 104 so that thecleaning element 114 is free to rotate. The cleaning element 114 in theillustrated embodiment is generally cylindrical in shape so thateffective removal of the debris can be accomplished by rotation of thecleaning element. The cleaning element 114 is sized so that it extendsacross the length of the solar panel array 10. The cleaning element 114is coupled to a motor that causes the cleaning element to rotate, whichcan be the same motor that rotates axle 106 or a different motor thatrotates the cleaning element in a different embodiment than illustrated.As the first and second wheels 108, 110 rotate such that the vehicle 100traverses the solar panels, the cleaning element rotates to mechanicallyremove debris from the surface of the solar panel array 10.

Referring now to FIGS. 2A, 2B, and 3, one side of the vehicle 100 isshown on the solar panel array 10 (the control housing 112 is removedfor ease of viewing). Although FIGS. 2A, 2B, and 3 illustrate only oneside of the vehicle, the opposite side is arranged in a generally thesame manner. The carriage 102 supports axle 106. First wheel 108contacts an upper surface of the solar panel array 10 and is axiallyaligned with and coupled to axle 106. The cleaning element 114 issupported by the carriage 102 and disposed on a first side of axle 106.The adjustable couple 120 and third wheel 116 are disposed on anopposite side of the axle 106. The adjustable couple 120 and travelerwheel 116 are spaced a distance D1 from the axle 106 and the cleaningelement 114 is spaced a distance D2 from the axle 106 (i.e., the thirdwheel 116 is located further away from the cleaning element than thefirst wheel 108). In this structural arrangement, the weight (W) of thecleaning element 114 results in a rotational force R1 about the axle 106in a first direction. The third wheel 116 is in contact with anunderside of the solar panel 10. Accordingly, the force between thethird wheel 116 and the underside of the solar panel result in arotational force R2 about the axle 106 that is in an opposite directionof the rotation force R1 caused by the cleaning element 114. F1 and F2are the reaction forces experienced by the traveler wheel and drivewheels, respectively. As can be seen, the cleaning element 114 iscantilevered to the front side of the vehicle with respect to axle 106and first wheel 108 so that the vehicle is “front heavy.” Since thethird wheel 116 counteracts the force generated by the cantileveredmounting of the cleaning element 114, the adjustment of the third wheel116 can affect the positioning of the cleaning element 114, as discussedin more detail below.

The third wheel 116 extends below the carriage 102 so that the thirdwheel 116 can contact an underside of the solar panel array 10 while thefirst wheel 108 contacts the upper side of the array. The third wheel116 is coupled to the carriage 102 via an adjustable couple 120. Theadjustable couple includes a first frame member 124 attached to thecarriage 102 and a second frame member 126 to which the third wheel 116is connected. Supports 128 and 130 extend between the first and secondframe members 124, 126. The two supports 128 and 130 prevent undesiredrotation between the frame 126 and the rest of the vehicle in order tomaintain alignment of the third wheel 116. One of the supports 130 canbe threaded and connected to the frame 124 such that rotation of handle132 causes rotation of the threaded support 130 and results in a changein the distance A between the two frame members 124 and 126. Adjustingthe distance between the two frame members 124, 126 causes the thirdwheel 116 to move with respect to the drive wheel 10 (i.e., in the frameof reference of the vehicle, the total vertical distance between thetraveler wheel and drive wheel is changed because the attachment pointfor the traveler wheel is moved with respect to the vehicle). If thesupport 130 is adjusted such that the distance between the two framemembers 124, 126 is increased (i.e., A2 is greater than A1), the vehiclecan then rotate about the first wheel 108 in the direction M such thatthe cleaning element 114 is lowered with respect to the top surface ofthe solar panel array, as show in FIG. 2B. If the support 130 isadjusted such that the distance between the two frame members 124, 126is decreased (i.e., A2 is less than A1), the vehicle can rotate aboutthe first wheel 108 in the opposite direction such that the cleaningelement 114 is raised with respect to the top surface of the solar panelarray. The ability to lower or raise the cleaning element 114 relativeto the solar panel surface allows for adjustment of the amount ofcontact between the cleaning element 114 (e.g., filaments of a rotatingbrush) and the panel surface in the field. This structure which allowsfor this kind of adjustment is useful both during initial setup as wellas during maintenance as the cleaning element 114 (e.g., brushfilaments) can wear down over time.

Referring to FIG. 3, the solar panel 10 is disposed between the firstwheel 108 and the third wheel 116. The third wheel 116 can have aconcave surface profile 134 such that profile complements the bottomedge 14 of the solar panel. As such, the third wheel 116 can contactboth a bottom surface 16 of the solar panel in addition to a sidesurface 18 of the solar panel. By contacting both the bottom and side ofthe solar panel, the traveler wheel can provide force in both thevertical and horizontal directions. This structural arrangement permitsthe traveler wheel to act as a guide which provides a normal forceoutwards on each side of the solar panel. This keeps the vehicle fromturning, and maintains the normal force pointing downwards, whichprevents the cleaning element 114 in the front from resting completelyon the top surface 12 by counteracting the force of gravity acting topull the brush down. As discussed above, the adjustable support 120allows for the adjustment of the traveler wheel, which provides for theraising and lowering of the cleaning element through a rotation actionof the vehicle. In addition, the adjustment provided by the adjustablesupport 120 also enables the vehicle to couple to solar panel arraysand/or guide tracks of differing thickness and geometries. Accordingly,the vehicle can be adjusted to couple to thicker solar panels byadjusting the adjustable support 120 which permits increasing thespacing between the frame members 124, 126. Conversely, the spacing canbe reduced to accommodate thinner solar panels.

Referring now to FIGS. 1B and 2B, the vehicle 100 includes a controlhousing 112 that includes at least one motor for providing drive powerto the vehicle. The motor can be coupled to the axle 106 in order totransmit power from the motor to the first wheel 108. In addition, thecleaning element 114 can be coupled to the axle 106 so that the powerfrom the motor can also be transmitted to the cleaning element to rotatethe cleaning element. A power transmission system 136 can couple theaxle 106 and the cleaning element 114 so that power from the motor canbe used to both rotate the first wheel 108 (causing the vehicle totranslate across the surface of the solar panel) and also rotate thecleaning element (causing the cleaning element to remove debris from thesurface of the solar panel). The power transmission system 136 caninclude a gear 138 connected to the axle 106 and a belt drive system 140that couples the cleaning element 114 to the gear 138. Accordingly, asthe axle 106 rotates, the gear 138 rotates which causes the belt drivesystem 140 to rotate, resulting in rotation of the cleaning element 114.The power transmission system 136 is structured and arranged such thatthe drive wheel 108 and the cleaning element 114 rotate in oppositedirections. As such, the cleaning element rotates opposite to thedirection in which the linear motion of the vehicle occurs. As thewheels drive forward, the reverse direction of rotation of the cleaningelement results in more effective cleaning.

In addition, the opposite rotation of the cleaning element counteractsthe torque generated by driving the drive wheels. Without powering ofthe cleaning element, as the motor applies a torque to drive the vehicleforward, the vehicle's body will react tending to do a ‘wheelie,’ i.e.,the brush tends to lift from the surface. However, because the drivewheels and the cleaning element are coupled to the motor, acounteracting effect results in the same manner, but with an oppositedirection. This effect is due to the torque required to drive the brush,and in particular to the torque required to start driving it, and thefact that the brush is moving opposite to the wheels. As a result,depending on which torque requirement is higher (i.e. the torque neededto accelerate the vehicle or the torque needed to start the cleaningelement), the vehicle will experience either one of a ‘wheelie’ or a‘diving’ effect. In the described arrangement, the torque required todrive the cleaning element is typically higher than the torque needed todrive the wheels and, therefore, the vehicle tends to dive forward as itaccelerates forward (i.e., the cleaning element is urged toward thesurface of the solar panel as a result of the torque). This is an addedbenefit of the design as it naturally ensures added cleaning elementpressure exists when driving forward to clean the panels, whilesimultaneously relieving that added pressure when driving back (i.e.,when the vehicle is driven in the opposite direction after a cleaningpass of the panel has been completed, the reverse torque directionstends to lift the cleaning element away from the solar panel, therebyreducing the pressure and friction therebetween). The torque effectstend to be strongest when the motion of the vehicle is started as thecleaning element overcomes static friction. The torque effect continuesafter startup, although not as strong, due to the sliding frictionexperienced between the cleaning element and the panel surface.

While a single motor may be used to rotate the drive wheels and thecleaning element, as discussed above, other motor arrangements arepossible. As it typically requires more power to drive the cleaningelement than it does to drive the wheels, arranging the motor to drivethe cleaning element directly and the drive wheel indirectly using apower transmission system can lower the cost of the power transmissionelements as they'd need to transfer less power and could therefore besmaller. On the other hand, shifting the motor to the front of thevehicle (i.e., proximate the cleaning element) will also shift theweight distribution of the vehicle and, in some cases, this may not bedesired. It is also possible to drive the drive wheels and the cleaningelement separately, either using separate motors for each and aclutching mechanism. For example, one possible benefit is that thecleaning element is not rotated after the vehicle completes its cleaningpass and is returning to its starting position as this will reduce powerconsumption and reduce wear on the cleaning element and panels. In otherarrangements, one motor can drive the brush and a second motor can driveonly one of the drive wheels (i.e., the other drive wheel is coupled tothe axle for free rotation and not driven rotation). Three motors canalso be used in which each drive wheel is driven by its own motor andthe brush is driven by the third motor. It is also possible to usemotors to drive the traveler wheels in addition to or instead of thedrive wheels (in this case, the brush is driven by another motor).

As discussed above with respect to the illustrated embodiment, the thirdand fourth wheels 116, 118 can have a concave surface 134 that contactsboth a horizontal and vertical surface (e.g., a bottom and a side) ofthe solar panel. In other arrangements, however, a guide assembly can beprovided on each side of the vehicle that includes two rollers. In a tworoller (per side) arrangement, one roller contacts the side of the solarpanel and the other roller contacts the underside of the solar panel.The two guide roller arrangement functions similar to the traveler wheelhaving a convex surface in that two guide rollers provide vertical andhorizontal forces to counteract the weight (W) of the cleaning element114 and maintain the vehicle coupled to and aligned with the solar panelwhile minimizing friction as the vehicle travels along the surface. Thislatter arrangement can be particularly suitable for installations inwhich the solar panel(s) are mounted with a tilt beyond a certainamount, such as 30 degrees, to provide both vertical and horizontalnormal forces while allowing the robot to translate along the solarpanel(s) with minimal friction. In addition, a second set of siderollers (one roller per side) can be included on the vehicle locatedcloser to the side of the vehicle having the cleaning element (e.g. inthe vicinity of the F2 Arrowhead in FIG. 2A). This additional set ofside rollers further assists in maintaining the vehicle in alignmentwith the solar panel array, especially in cases in which the vehiclespans wide or multiple solar panels.

Thus, the vehicle 100 can be widened to span multiple solar panels. Eachof the carriages 102, 104 of the vehicle can couple to the outermostside of the outermost solar panel in the array. In such an arrangement,the vehicle can clean multiple solar panels in a single pass. The axleand cleaning element can be elongated to accommodate the width of thesolar panel(s). A frame member 142 can extend between the two carriagesto provide additional structural support so that the carriages movetogether and maintain alignment.

Another result of the structural arrangement of the vehicle is that thevehicle has a certain degree of “bounciness” as it traverses the panels.This bounciness comes from a combination of the materials used in thedrive and traveler wheels and of any bumps or protrusions that thewheels might encounter. For example, harder materials will result in astiffer vehicle structure while softer, rubber-like materials will actas a spring-suspension and provide some bounciness (polyurethane coatedwheels with a Shore A hardness of 60 A for the drive wheels and 40 A forthe traveler wheels can be used). Also, the height of the cleaningelement relative to the surface will vary slightly as the wheels of thevehicle overcome obstacles or protrusions such as the edges of the panelframes, the gaps between panels, misalignment between one panel and thenext or even some debris on the panels such as hardened bird feces oraccumulated sand. Since the traveler wheels can be flexible and performlike a spring-suspension, the reduction in force required to hold thecleaning element up (due to the normal force created by the interactionof the cleaning element and the surface) causes the system todynamically balance in a position that is higher than if there was nonormal force between the cleaning element and the panels (i.e., if thecleaning element were not touching the panel). Therefore, the vehicleallows for a small degree of automatic adjustment.

The cleaning element 114 can be a brush with bristles or a cloth brushinstead of using plastic filaments. If a cloth cleaning element is used,the normal force on the cleaning element might be much less significant(negligible if the cleaning element were not spinning).

In other arrangements, the distance D1 between the drive wheels and thetraveler wheels can be reduced to zero (i.e., the first wheel 108 can bevertically aligned with the third wheel 116).

The present design is unique in that it puts the cleaning element infront of the wheels of the vehicle, solving a problem of reaching theend of the surface to be cleaned. Additionally, this arrangement reducesthe number of moving parts on the cleaning vehicle, thus allowing forimproved mechanical reliability and reduced cost. Additionally, thisdesign allows us to adjust the cleaning vehicle to fit onto solar panelsof various depths, making it easier to use on different systems withvery little modification.

It should be clear that the vehicle is designed to ride directly on theedges of standard PV (photovoltaic) solar panel modules and that noadditional tracks are required. The present design is suitable for useon both framed as well as frameless PV modules. In the case of framedmodules, the wheels of the vehicle simply ride directly on the Aluminumframe on the PV modules. On the other hand, in the case of framelesspanels, the wheels of the vehicle will ride directly on the module'smain glass panel. In that case, the designer should consider thestrength of the panel and strike a balance in the design parameters toensure that the moment exerted by the vehicles wheels (on account of itbeing front heavy) will not break the glass. Additionally, by removingone of the support bars, the roller can be rotated outwards on theremaining support bar, for easier mounting in the case that the robotcleaning device cannot be rolled onto the end of the panels.

The vehicle can include an adjustment screw for adjusting the height ofthe bottom wheel (traveler wheels). This in turn results is: a) theability to adjust the vehicle to work on different types of solar panels(with different frame heights) while on the field; and b) the ability tolower or raise the brush relative to the panel surface to control theamount of contact between the brush filaments and the panel surface onthe field (this is useful both during initial setup as well as duringmaintenance as the brush filaments wear down over time). As describedherein, there is a moment created by the reaction forces F1 and F2 as itcan be controlled by a user changing D1, D2 and other vehicle designparameters. The user will look at the statics and dynamics of thevehicle and make sure that there is enough traction out of both wheelsand also the wheel material is selected in order to obtain the desiredspringy nature thereof. It will also be appreciated that the “lower” ofthe bottom wheel using the adjustment screw does not result in thebottom wheel moving its position but instead, the attachment pointbetween the bottom roller and the rest of vehicle rises away from theroller, thus allowing the brush to lower as the vehicle tilts forward.

In addition, as shown in FIG. 4, the “traveler wheels” can take anynumber of different configurations and arrangements. For example, whileFIG. 3 shows a single traveler wheel (i.e., the third wheel 116), itwill be appreciated that, as shown in FIG. 4, more than one travelerwheel can be associated with and coupled to each carriage as discussedbelow. In addition, the wheels are not limited to having a concave orV-shaped construction and other constructions can equally be used. Forexample, in the embodiment of FIG. 4, the wheels have smooth circularshaped outer surfaces.

In the embodiment of FIGS. 4 and 5, the counter-balancing function isseparated from the sideways alignment function. More specifically, FIG.4 shows a vehicle 200 with a first carriage 210 (similar to carriage104) and a second carriage 212 (similar to carriage 102) being spacedtherefrom and coupled thereto by a cross support member 219. The crosssupport member 219 can be in the form of an elongated support structurethat is attached (fastened) at its ends to the first and secondcarriages 210, 212. The cross support member 219 has a forward face 222and a rear face 224. Similarly, each of the first and second carriages210, 212 has a forward facing end and a rearward facing end. The crosssupport member 219 can be formed of any number of different materials,including but not limited to metals, rigid plastics, etc.

As shown in FIGS. 4 and 5, the rearward facing end of each of thecarriages 210, 212 has a downwardly extending arm 211. Along thedownwardly extending arm 211, one or more holes 213 are formed. Theillustrated embodiment has three spaced holes 213 along the arm 211.

The vehicle 200 is constructed such that each of the first and secondcarriages 210, 212 includes a side roller 220 and a bottom (up-stop)roller 230. While FIGS. 4 and 5 show a single side roller 220 and asingle bottom roller 230 being used, it will be understood that morethan one side roller 220 and more than one bottom roller 230 can be used(See, FIG. 6 which eliminates a bracket to show the wheel 110). In thisembodiment, the roller 220 and roller 230 are not adjustable unlike theprevious embodiment. More specifically, the side roller 220 is mountedon an axle (that is oriented perpendicular to the longitudinal axis ofthe carriage) and is positioned such that the contacting surface of theside roller contacts a side wall of the panel 10. The bottom roller 230is mounted on an axle (that is oriented parallel to the longitudinalaxis of the carriage) and is positioned such that the contacting surfaceof the bottom roller contacts a bottom wall of the panel 10.

The holes 213 allow for different positioning of the bottom roller 230relative one of the respective first and second wheels 108, 110, therebyaccommodating panels 10 having different thicknesses.

FIGS. 4 and 5 also show an arrangement in which only one of the firstand second wheels 108, 110 is driven and in particular, in theillustrated embodiment, the second roller 110 is the one which isdriven. The second wheel 110 is mounted to a first wheel support 240(similarly, the first wheel is mounted to an identical or similar secondwheel support (not shown) that is mounted to the carriage 210). Each ofthe first and second wheel supports 240 can be in the form of a bracketwhich attaches at its ends to an inner face of the correspondingcarriage 210, 212. The first wheel 108 is rotatably positioned betweenthe first wheel support 240 and the first carriage 210 and the secondwheel 110 is rotatably positioned between the second wheel support 242and the second carriage 212. A first motor 250 is operably coupled tothe first wheel 108 to control rotation thereof. The first motor 250 ismounted along an outer face of the first carriage 210. A second motor252 is also mounted to the outer face of the first carriage 210 and isoperably coupled to the cleaning element 114 to controllably rotate thecleaning element 114.

Since only one motor 250 is used to drive the vehicle 200 along thepanel 10, the other wheels along the top of the panel 10 are passive(slave) wheels. In the illustrated embodiment, the second wheel 110 isthus not directly driven by the motor 250 (i.e., no power transmissionto the second wheel 110). In addition, since the cleaning element 114and first wheel 108 are independently driven by motors 252, 250,respectively, there is not power transmission between the cleaningelement 114 and the drive wheel (i.e., wheel 108).

FIGS. 4 and 5 also show that the vehicle 200 includes an additionaloptional top wheel, namely, a fifth wheel 260. Like the second wheel110, the fifth wheel 260 is a passive wheel and is not actively drivenby a motor. The fifth wheel 260 can be mounted to the cross supportmember 219 and more particularly, the fifth wheel 260 is mounted to awheel bracket 270 (e.g., U-shaped bracket) that is attached to the rearface 224. The fifth wheel 260 in the illustrated embodiment is centrallylocated along the cross support member 220. It will be appreciated thatthe first, second and fifth wheels 108, 110, 260 are all oriented suchthat a single axis passes through the axles about which the wheelsrotate. This arrangement ensures that when the vehicle 200 is placed onthe top of the panel 10, each of the wheels 108, 110, 260 seats againstthe top of the panel 10. The fifth wheel 260 is thus positioned toprovide support for weight if needed.

FIG. 6 shows another vehicle 300 that is constructed to include two siderollers 220 and one bottom (up-stop) roller 230 per each carriage. Thetwo side rollers 220 are spaced apart with one top wheel being at leastpartially disposed between the two side rollers 220. The one bottomroller 230 is located at the rear end of the carriage.

Based on the foregoing, it should be understood that the invention canbe realized in a number of ways, at differing levels of specificity, ascan be gleaned from the following points.

According to one embodiment, a cleaning vehicle for cleaning a surfacehaving first and second top side edges and first and second bottom sideedges is disclosed and has the following features:

first and second carriages;

an axle extending between the first and second carriages;

first and second drive wheels coupled to opposite ends of the axle;

at least one motor supported by one of the first and second carriagesand coupled to the axle to transmit power from the motor to the axle soas to cause the first and second drive wheels to rotate in a firstdirection;

a cleaning element extending between the first and second carriages andsupported thereby, the cleaning being disposed on one side of the axleand spaced therefrom by a first distance;

first and second traveler wheels disposed on an opposite side of theaxle and spaced therefrom by a second distance;

first and second adjustable couples, each traveler wheel being connectedto one of the first and second carriages by a respective one of theadjustable couples, wherein the adjustable couples define a spacingbetween a respective carriage and traveler wheel that can be altered byadjustment of the adjustable couple, the spacing being sized to receiveat least a portion of the surface to be cleaned between the drive wheelsand traveler wheels, and further wherein altering the spacing between arespective carriage and traveler wheel causes the cleaning element torotate about the drive wheels.

The subject matter described above is provided by way of illustrationonly and should not be construed as limiting. Various modifications andchanges can be made to the subject matter described herein withoutfollowing the example embodiments and applications illustrated anddescribed, and without departing from the true spirit and scope of thepresent invention.

What is claimed is:
 1. A cleaning vehicle for cleaning a surface of anobject comprising: first and second carriages; first and second wheelscoupled to the first and second carriages, respectively, for placementalong a top surface of the object; at least one motor operativelycoupled to at least one of the first and second wheels to define a driveassembly; a cleaning element extending between and being supported bythe first and second carriages; third and fourth wheels; and a firstadjustable couple that is coupled to the first carriage and a secondadjustable couple that is coupled to the second carriage, wherein thefirst adjustable couple defines a first spacing between the firstcarriage and the third wheel and the second adjustable couple defines asecond spacing between the second carriage and the fourth wheel, thefirst and second spacings being sized to receive at least a portion ofthe object to position the vehicle on the surface to be cleaned; whereinthe cleaning element is disposed on one side of an axis passingcentrally through the first and second wheels and spaced therefrom by afirst distance; wherein the third and fourth wheels are disposed on anopposite side of the axis and spaced therefrom by a second distance; andwherein the first and second adjustable couples each comprises a supportmember configured to move the third and fourth wheels vertically withrespect to the first and second wheels, respectively, such that thevertical movement of the third and fourth wheels results in the raisingor lowering of the cleaning element with respect to the surface of theobject.
 2. The cleaning vehicle of claim 1, wherein the object comprisesa solar panel and the surface comprises a top surface thereof and thefirst and second wheels and the cleaning element contact the surface tobe cleaned.
 3. The cleaning vehicle of claim 2, wherein the solar panelfurther includes a bottom surface and a pair of opposing side surfacesthat extend between the top and bottom surfaces.
 4. The cleaning vehicleof claim 3, wherein the third wheel seats against both one side surfaceand the bottom surface and the fourth wheel seats against both the otherside surface and the bottom surface.
 5. The cleaning vehicle of claim 1,wherein each of the third and fourth wheels has one of a concave shapeand a V-shape.
 6. The cleaning vehicle of claim 1, further including anaxle extending between the first and second carriages and coupled to thefirst and second wheels, wherein the motor is configured to rotate theaxle so as to cause the first and second wheels to rotate in a firstdirection.
 7. The cleaning vehicle of claim 6, wherein the motor ismounted to one of the first and second carriages.
 8. The cleaningvehicle of claim 6, wherein the first and second adjustable couples areconfigured such that altering the first and second spacings between thefirst and second carriages and the third and fourth wheels,respectively, causes the cleaning element to rotate about the axle. 9.The cleaning vehicle of claim 6, wherein the cleaning element iscantilevered relative to a front side of the vehicle with respect to theaxle and the first and second wheels causing the vehicle to be frontheavy.
 10. The cleaning vehicle of claim 1, wherein the cleaning elementcomprises a brush with bristles.
 11. The cleaning vehicle of claim 6,wherein the cleaning element is operatively coupled to the axle so thatrotation of the axle is translated into rotation of the cleaningelement.
 12. The cleaning vehicle of claim 11, wherein the operativecoupling between the cleaning element and the axle is accomplished witha transmission system that couples the axle to the cleaning element suchthat power from the at least one motor rotates both the first and secondwheels and the cleaning element.
 13. The cleaning vehicle of claim 12,wherein the transmission system includes a gear connected to the axleand a belt drive system that couples the cleaning element to the gearsuch that rotation of the axle is translated into rotation of the gearwhich in turn causes the belt drive system to rotate resulting inrotation of the cleaning element.
 14. The cleaning vehicle of claim 1,wherein the first and second wheels rotate in a first direction, whilethe cleaning element rotates in an opposite second direction.
 15. Thecleaning vehicle of claim 1, wherein when the vehicle is driven in aforward direction, torque required to accelerate the vehicle is lessthan torque required to rotate the cleaning element and therefore, asthe vehicle drives forward, the vehicle dives forward causing thecleaning element to be urged against the surface to be cleaned andconversely, when the vehicle is driven in a rearward direction, reversetorque directions causes the cleaning element to be lifted away from thesurface to be cleaned.
 16. A cleaning vehicle for cleaning a surface ofan object comprising: first and second carriages; first and secondwheels coupled to the first and second carriages, respectively, forplacement along a top surface of the object; at least one motoroperatively coupled to one of the first and second wheels to define adrive assembly; a cleaning element extending between and being supportedby the first and second carriages at a location forward of the first andsecond wheels; and third and fourth wheels, the third wheel beingadjustably mounted relative to the first wheel and the fourth wheelbeing adjustably mounted relative to the second wheel, the third andfourth wheels being configured such that the object is received betweenthe third and fourth wheels and the respective first and secondcarriages; wherein the first wheel is disposed between the cleaningelement and the third wheel; wherein the second wheel is disposedbetween the cleaning element and the fourth wheel; and wherein thecleaning element is mounted in a cantilevered orientation relative to afront side of the vehicle with respect to an axle connecting the firstand second wheels and the first and second wheels, causing the vehicleto be front heavy, and the third and fourth wheels are positioned tocounteract a force generated by the cantilevered mounting of thecleaning element such that adjustment of the third and fourth wheelsrelative to the first and second wheels causes repositioning of thecleaning element relative to the surface to be cleaned.
 17. The cleaningvehicle of claim 16, wherein the third and fourth wheels are forplacement against an underside of the object resulting in rotationalforce R2 about the axle that is in an opposite direction of therotational force R1 about the axle caused by the cantilevered mountedcleaning element, thereby counteracting the rotational force R1 andpreventing the cleaning element from completely resting on the surfaceto be cleaned due to gravitational force.
 18. The cleaning vehicle ofclaim 16, further including a first adjustable couple that is coupled tothe first carriage and a second adjustable couple that is coupled to thesecond carriage, wherein the first adjustable couple defines a firstspacing between the first carriage and the third wheel and the secondadjustable couple defines a second spacing between the second carriageand the fourth wheel, the first and second spacings being sized toreceive at least a portion of the object to position the vehicle on thesurface to be cleaned.
 19. The cleaning vehicle of claim 16, whereinadjustment of the third and fourth wheels relative to the first andsecond wheels results in a lower or raising of the cleaning element,thereby allowing for adjustment of an amount of contact between thecleaning element and the surface to be cleaned.
 20. The cleaning vehicleof claim 16, wherein each of the third and fourth wheels has a concaveprofile configured such that each of the third and fourth wheelscontacts both bottom and side surfaces of the object resulting in aforce being provided by each of the third and fourth wheels in bothvertical and horizontal directions.
 21. The cleaning vehicle of claim18, wherein each of the first and second adjustable couples includes afirst frame member fixedly attached to one of the respective first andsecond carriages and a movable second frame member, wherein a distancebetween the first and second frame members can be varied by altering aposition of the second frame member relative to the first frame member,the second frame member carrying one of the third and fourth wheels,wherein adjustment of the distance between the first and second framemembers translates into rotation of the respective first or secondcarriage about the axle resulting in lowering or raising of the cleaningelement.
 22. A cleaning vehicle for cleaning a surface of an objecthaving a top surface and an opposite bottom surface comprising: firstand second carriages; an axle extending between the first and secondcarriages; first and second drive wheels coupled to the axle to form adrive assembly, the first and second drive wheels for placement on thetop surface; at least one motor operatively coupled to the driveassembly; a cleaning element extending between and being supported bythe first and second carriages, the cleaning element for placement alongthe top surface; and first and second traveler wheels for placementalong at least a portion of the bottom surface, the first traveler wheelbeing adjustably mounted relative to the first drive wheel such that adistance therebetween can be adjusted and the second traveler wheelbeing adjustably mounted relative to the second drive wheel such that adistance therebetween can be adjusted; wherein the cleaning element isdisposed on one side of the axle, and the first and second travelerwheels are disposed on an opposite side of the axle such that the firstand second traveler wheels serve to counteract a force generated by thecleaning element in a direction toward the top surface; wherein rotationof the first and second carriages about an axis of the axle throughadjustment of the distance between the first and second traveler wheelsand the first and second drive wheels causes a raising or lowering ofthe cleaning element relative to the top surface.
 23. The cleaningvehicle of claim 22, wherein the cleaning element is mounted in acantilevered orientation relative to a front side of the vehicle withrespect to the axle and the first and second drive wheels causing thevehicle to be front heavy and the first and second traveler wheels arepositioned to counteract a force generated by the cantilevered mountingof the cleaning element such that adjustment of the first and secondtraveler wheels relative to the first and second drive wheels causesrepositioning of the cleaning element relative to the surface to becleaned.
 24. The cleaning vehicle of claim 22, wherein the objectcomprises a solar panel.
 25. A method for cleaning a top surface of anobject comprising the steps of: positioning a vehicle on the top surfaceof the object and alongside edges of the object such that first andsecond drive wheels of the vehicle seat against the top surface and acleaning element is positioned also along the top surface; adjustingfirst and second traveler wheels of the vehicle so as to be in contactwith at least one of a side surface and bottom surface of the object,the first and second traveler wheels being mounted to a frame to which:(1) an axle supporting the first and second drive wheels is mounted,wherein the cleaning element is disposed on one side of the axle and (2)the cleaning element is rotatably mounted, whereby adjustment of thefirst and second traveler wheels through adjustment of a distancebetween the first and second traveler wheels and the first and seconddrive wheels, respectively, causes the vehicle to rotate about an axisof the axle resulting in either the cleaning element being lowered orraised relative to the top surface; and driving the vehicle along thetop surface by causing rotation of the axle.
 26. The method of claim 25,wherein the cleaning element is mounted in a cantilevered orientationrelative to a front side of the vehicle with respect to the axle and thefirst and second drive wheels causing the vehicle to be front heavy, andthe first and second traveler wheels are positioned to counteract aforce generated by the cantilevered mounting of the cleaning elementsuch that adjustment of the first and second traveler wheels relative tothe first and second drive wheels causes repositioning of the cleaningelement relative to the surface to be cleaned.